This in only possible on independent instances. Separate nodes on elements on each side of the crack can be created by defining a seam. When simply creating a partition to represent the crack, the elements on both sides of the partition will be connected to each other: they will share nodes. Using the Merge/Cut Instances feature in the assembly module a part containing a partition for the crack can be made. In this case, the face is partitioned, and the Partition Cell: Extrude/Sweep Edges tool is used to extrude the partition on the face.Īlternatively, a separate shell part can be made that represents the crack. A partition is made representing the crack. First of all, the crack itself needs to be simulated. There are several things to pay attention to when modelling a crack. In this blog I will explain how to set up a simulation to determine the stress intensity factor or J-integral. Abaqus can calculate such outcomes for a crack, which can then be compared to critical values to determine whether or not a crack will propagate. Another is the J-integral, which describes how much strain energy is released per unit fracture surface area. One of these is the stress intensity factor (K), which describes how quickly the stress increases towards the crack, assuming a linear elastic material. Because the stress at a crack depends strongly on the mesh/thickness of the crack, looking at stress to determine whether a crack will propagate does not work well. Because this thickness is very small, it is difficult to measure and take into account numerically. In the real world, perfectly sharp cracks do not exist a crack will always have a finite thickness. The loading will be localised in a single element and therefore the results will depend strongly on the mesh, which is unwanted. In a simulation it is not possible to obtain an infinitely large stress. In a perfectly sharp crack, loading is applied to a single point, causing a singularity with an infinitely large stress. Simulating this requires special techniques, especially for sharp cracks. In many cases it is important to know whether a crack will propagate.

Crack propagation in abaqus cae